Reenable DynamicRotationList for language-switching-aware IMEs

In order to reenable DynamicRotationList for
language-switching-aware IMEs, this CL reverts
I84291fd4a7d6192b3bd0c366c49 with fixing a bug that the dynamic
rotation state is reset even when the list of input methods is
not changed.

With this CL, the dynamic rotation state is preserved when the
enabled input methods is not changed actually.

BUG: 7043015
Change-Id: I506828c7a363e79f1c767eeb28f0d3746ff1cb0d